Does the National Immunisation Register stack up? Quantifying accuracy when compared to parent-held health record books.

AIM: The National Immunisation Register (NIR), which is derived from general practice management systems, is an important tool for the provision of clinical services, national immunisation programme evaluation and immunisation research in New Zealand. However, the accuracy of the NIR data has not yet been quantified. This study aimed to examine, describe and quantify the extent of discrepancy in the NIR compared to Well Child Tamariki Ora parent-held health record books (Health Books). METHOD: Immunisation data for vaccinations given between birth and four years old for children born between 2006 and 2019 were compared between the Health Books and the NIR. Health Book records were used as the reference standard to calculate performance measures: sensitivity, specificity, positive and negative predictive values for the NIR. RESULTS: Overall, NIR performance was high: sensitivity ranged from 90% to 93%, specificity from 78% to 85%, the positive predictive value from 91% to 94% and the negative predictive value from 77% to 84%. NIR performance was higher for National Immunisation Schedule (NIS) vaccines compared with non-NIS vaccines. CONCLUSION: This study indicates the NIR data accuracy generally performs well compared with international equivalents, especially for NIS vaccine records. Further work is required to ascertain why discrepancies between the Health Books and NIR continue to occur, with particular attention to important subgroups and translating records across from migrant populations. Also, future work is required to understand the accuracy of vaccination records for groups who experience lower-quality healthcare and a higher burden of infectious diseases.

Pertussis Vaccination Failure in the New Zealand Pediatric Population: Study Protocol.

Pertussis vaccines have been effective at reducing pertussis-associated morbidity and mortality. However, they have a complex array of limitations, particularly associated with the duration of protection against clinical disease and imperfect immunity (carriage and transmission). Little is known about risk factors for pertussis vaccination failure. Understanding pertussis vaccination failure risk is most important in the paediatric population. This study aims to investigate risk factors for pertussis vaccination failure in (1) infants between birth and six weeks of age born to mothers who received pertussis booster vaccinations during pregnancy and (2) infants after the completion of the primary series (approximately five months old) to four years old. This will be achieved in a two-step process for each study group. Pertussis vaccination failure cases will first be described using a case series study design, relevant case characteristics will be sourced from six national administrative datasets. The case series study results will help select candidate risk factors (hypothesis generating step) to be tested in the retrospective cohort study (hypothesis testing step. Pattern analysis will be used to investigate risk factor patterns in the cohort study. The identification of higher risk groups enables targeting strategies, such as additional doses, to better prevent pertussis disease.

Evaluating FINDRISC as a screening tool for type 2 diabetes among overweight adults in the PREVIEW:NZ cohort.

AIMS: This study aimed to evaluate the efficacy of a high (≥12) Finnish diabetes risk (FINDRISC) score in identifying undiagnosed prediabetes and type 2 diabetes (T2D) in an New Zealand population of overweight and obese individuals, across a variety of ethnic groups. METHODS: We estimated the efficacy of elevated FINDRISC scores in predicting prediabetes and T2D in 424 overweight adults with no prior diagnosis recruited for the PREVention of diabetes through lifestyle Interventions in Europe and Worldwide (PREVIEW) study. All participants who completed the FINDRISC questionnaire during a pre-screening phase with a score of ≥12 were then screened using a 2h oral glucose tolerance test (2h-OGTT) to identify undiagnosed dysglycaemia. RESULTS: Of the 424 participants, 65% (n=280) were pre-diabetic and 7% (n=32) had undiagnosed T2D. A higher FINDRISC score was significantly associated with prediabetes and T2D (P=0.02). There was a significant association between ethnicity and glycaemic status (normal vs prediabetes/T2D, P=0.02). Increasing the FINDRISC cut-off to ≥15 resulted in a non-significant increase in the proportion of participants correctly classified with dysglycaemia. ROC-AUC=0.6 with sensitivity=0.6026 (95% CI: 0.5459-0.6573) and specificity=0.5536 (95% CI: 0.4567-0.6476). Isolated impaired fasting glucose (IFG) was more efficient in predicting dysglycaemia than isolated impaired glucose tolerance (IGT). CONCLUSIONS: The FINDRISC questionnaire is a useful and efficacious screening tool to identify unknown prediabetes and T2D in overweight New Zealanders, particularly in Maori individuals.